When I was doing post graduate work, there was a very attractive girl in my class that knew I was a personal trainer.
I basically gave her some tips here and there, and would watch her train. She was pretty damned hardcore (squats, chins, dips).
After a few months of training, she is looking flat out awesome. I compliment her gains. She then tells me she is taking clenbuterol.
I have always been natural, and was blown away about how nonchalant she was about her use. She was incredulous about my natural status.